1. Technical Field
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device detecting an abnormal operation such as a hacking attempt and a method thereof.
2. Discussion of the Related Art
A memory card is widely used in a small electronic device such as a digital camera, a PDA, or a mobile communication device, as it is a device capable of storing data. The memory card includes a non-volatile memory such as a flash EEPROM. The memory card has various shapes and sizes such as a smart card, a multi media card MMC, a secure digital SD card, or a xD-picture card, for example, and may store multiple types of data representing a picture, a document, music, a program, etc. All memory cards essentially have the same function of storing data.
Because the memory card is portable, it can be embedded in a credit card, a mobile communication device, or used in financial transactions, etc., according to stored information. The stored information can be biographical information, financial information, or authentication information. When stored data which requires to be secured are accessed, copied, forged, or otherwise compromised, the user can be placed at great risk of identity theft and financial loss. Therefore, securing the data is important.
One of the methods for improperly accessing (hacking) data stored in a memory card is breaching a protective film, e.g., a silicon dioxide film (SiO2), covering the surface of a chip of the memory card, and monitoring a metal line exposed to the surface of the chip by using an oscilloscope.
The memory card may include a plurality of photo sensing elements in a chip as a method for sensing an abnormal operation such as a hacking attempt. When a protective film of the chip inside the memory card is breached for improper purposes, the plurality of photo sensing elements may sense an abnormal operation by outputting a control signal in response to an incident light. A central processing unit (CPU) may be reset in response to the control signal. Accordingly, data stored in a memory may be protected.
Because the size of a photo sensing cell is big, it may be difficult to place a number of photo sensing cells in the memory card, or the photo sensing cell may not be properly positioned within the chip of a memory card. Accordingly, the memory card may not reliably protect data as it can sense an abnormal operation only in a specific area proximal to the photo sensing cell.
Also, the photo sensing cell may not sense an abnormal operation when an incident light is less intense than a level which the photo sensing cell may sense. Accordingly to properly secure a memory card, the memory card may need to have metal covering most or all parts of the chip.
A need therefore exists for a sensing part capable of sensing an abnormal operation of a memory chip, and a method for protecting data capable of sensing an abnormal operation in any operational environment and during any operation is required.